Duluth, MN (KDAL) - A Twin Ports employer plans on adding a shift. A-A-R says it will add a third line of maintenance to their Duluth facility. The aerospace and defense contractor maintains planes for Air Canada and they employ 276 Northlanders. The Illinois-based company reopened the shuttered 188-thousand square foot building last November with one line of maintenance. Earlier this year they added a second line. A-A-R’s growth has been seen outside of Duluth. They recently opened a sixth North American hangar in Louisiana, where they’re planning on employing 500 workers by 2017.